When disassembling a rail for replacement, various small metallic articles (e.g., spikes, tie plates, and anchors) are removed and laid upon the railroad bed. Since it is desirable to clear the railroad bed of such metallic articles and re-use such articles to the extent possible, several magnetic wheel-type devices for picking up these metallic articles have been previously developed. For example, U.S. Pat. Nos. 4,478,152 and 4,225,429 disclose railroad scrap pick-up machines having a magnetic wheel device that is useable with a specially designed rail-mounted vehicle. The disclosed devices pick up scrap articles such as tie plates and rail spikes lying on the railroad bed.
Smaller metallic filings of iron are also found along rail beds. Such iron filings are generally produced by rail grinder trains which are employed on railroads to grind the top surface of the rail in order to extend rail life. Other sources of metallic particles include wear debris, such as wheel to rail contact (especially in curve negotiation), brake shoe dust, ore droppings from transport, etc.
When a train travels along the rail bed, these small iron filings (or other metallic particles) may become airborne due to the strong air currents generated by the movement of the engine and railcars over the track. Once airborne, the particles may be blown into the railcars. This particle contamination can create problems with certain types of freight as will next be described.
New motor vehicles (such as cars, light trucks, vans, etc.), as well as a variety of other goods, are commonly transported on railroad cars from manufacturing plants to various destinations. Motor vehicles are usually transported in multi-level auto rack railroad freight cars. These multi-level rail cars usually have openings and gaps in their side wall screens and end doors which permit entrance of contaminants such as fine metallic particles and/or dust particles coming off the railroad bed during transit. Under the right conditions of temperature, air current speed, and humidity, these contaminants become airborne from the railroad bed, settle on the transported motor vehicles and then bloom into rust. The main areas of rust concern tends to be the horizontal painted surfaces of the motor vehicles being transported. This rust damage can even occur on the transported motor vehicles after the vehicles have been deramped and set out on lots awaiting distribution. This problem has existed for many years and motor vehicle manufacturers who ship on the railroad lines want to prevent this problem. However, the increased activity of rail grinding by railroad companies has served to aggravate this problem.
To date, solutions to eliminate the problem of contamination from airborne particles have been expensive and impractical. For example, one proposed solution is to wash the automobiles before the particles have become anchored to the paint as a result of the rusting process. A second proposed solution was based on tests indicating that air flows inside typical auto racks occurs with the air entering the side screens (in the middle of the car), migrating to both ends of the car, and being expelled near the end doors. Therefore, to alleviate this problem, prototypes have been built with solid side screens. The solid side screens noticeably reduce air flow inside the auto rack. The reduced airflow reduces the amount of dust contamination, and also causes particles to "fall out" or "settle out" of the air flow before reaching auto paint surfaces. However, it is believed that completely sealing the rail car may lead to toxic fume problems for auto loaders and unloaders.
Therefore, there is a need to minimize the high cost of either pre-treating autos with coatings or repairing damage at the auto's destination by reducing or completely eliminating the amount of metallic particles entering auto rack rail cars. In particular, it would be considered beneficial to minimize the amount of magnetic iron/iron oxide particles entering auto rack rail cars, or other particles which create rust problems on automobiles carried as freight. More generally, there is a need for minimizing the intrusion of contaminants (such as metallic grit and dust particles) into a rail car to prevent or reduce damage to motor vehicles and other goods being transported. The present invention helps to alleviate the above contamination problem as discussed in greater detail below.